Monday, November 28, 2016

For at least a year now, I've seen this math problem being floated about the various new websites. And I don't understand why it is such a big deal.

The problem involves a simple math problem that many students first learned in an intro algebra class:

Now, any child learning something like this would have to also learn about the SEQUENCE of operations that one has to perform to do this correctly. If you simply start to enter this into your calculator in order that it is written, you'll get the wrong answer.

And of course, you have to know that dividing by 1/3 is equivalent to multiplying by 3.

There are many mnemonic guides that one can use to know which one to perform first. In this case, you first perform the division, thus simplifying the equation into:

9 - 9 + 1 = ?

which will obviously leave you with the answer of 1.

This problem is getting rather a lot of publicity because it claims that a lot of people didn't get the right answer for something that seemingly looks very simple. My response to that is: Yeah, so?

When one learns this rule in school, one is given many similar problems of this type. This is not an unusual problem, and certainly something a lot of people will get wrong if they don't remember what the rule is. This is not surprising.

Sunday, November 20, 2016

I hate to keep beating a dead horse, but this question DOES keep popping up regularly on many websites and forums. And when a new article tries to explain this again, it bares repeating.

This article tries to explain what is so "spooky" about quantum entanglement. The "spookiness" comes from Einstein's description of quantum mechanics which he showed, via the EPR-type measurement, that information about a quantum property can be "transferred" instantaneously between entities across space.

You'll notice that in the article, the author had to go back and explain the concept of superposition of states. This is what makes this type of phenomenon different than the classical phenomenon.

Let’s go over the issue of entanglement to start. The experiment is
normally done with photons: you pass a single quantum of light through a
specialized material (e.g., a down-conversion crystal) which splits it
into two photons. These photons will be entangled in a particular sense,
where one has a spin, or internal angular momentum, of +1, and the
other has a spin of -1. But you don’t know which is which. In fact,
there are some experiments you can do where, if you had large numbers of
these photons, you’d see a difference between:

the statistical results if the spin was +1,

the statistical results if the spin was -1,

or the statistical results if the spin was undetermined.

If you had been following this blog for a while, this is the same attempt that I made to explain quantum entanglement before. This is because most people who are just trying to understand this only pay attention to the "entanglement" aspect of it, i.e. a property being "linked" over a distance, rather than actually understanding the superposition concept, which is actually more well-established. It is the presence of superposition, and the lack of classical realism on a system (before a measurement) that separates this from an ordinary classical conservation-of-quantity phenomenon.

According to Prescod-Weinstein, the slogan
“Make America Great Again” is problematic because it presupposes that
the United States was great when African-Americans were “more likely to
be hanged from a tree than welcomed in the physics community” and when
Nazi war criminals “became central to the American scientific
establishment.”

“If
APS’s leadership had any imagination — or concern for those of us who
are being threatened by emboldened racists/transphobes/etc.,” she
continued, “they would have said, ‘We urge President-elect Trump to
finally actually make America great through the allocation of resources
that will combat discrimination and hate in all their forms.’”

All I can say is that these next few years are going to be "interesting".